M. Heydari-Malayeri - Paris Observatory

1) General: The process of making something square; the act of squaring.
2) Math.: The act or process of constructing a → square
with an area equal to that of a specified surface, especially a surface bounded by a curve.
3) Astro.: The position of a planet or the Moon when it makes a 90° angle with the
Sun as seen from Earth.

From L. quadratura, from quadrat(us) p.p. of
quadrare "to make square."

Constructing a square whose area equals that of a given circle.
This was one of the three geometric problems of antiquity. It was finally
proved to be an impossible problem when π was proven to be transcendental
by Lindemann in 1882. Same as → squaring the circle.